Vacuum cleaner

ABSTRACT

A vacuum cleaner is provided with a chassis and a suction nozzle coupled with the chassis for both vertical and horizontal movement relative to the chassis. The nozzle can be configured to automatically move vertically upon encountering a predetermined amount of resistance to forward or rearward movement of nozzle over a surface to be cleaned.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of patent application Ser. No.16/122,101, filed Sep. 5, 2018, now allowed, which is a continuation ofU.S. patent application Ser. No. 15/071,698, filed Mar. 16, 2016, nowU.S. Pat. No. 10,105,024, issued Oct. 23, 2018, which claims the benefitof U.S. Provisional Patent Application No. 62/133,673, filed Mar. 16,2015, all of which are incorporated herein by reference in theirentirety.

BACKGROUND

Vacuum cleaners are provided with a vacuum collection system forcreating a partial vacuum to suck up debris (which may include dirt,dust, soil, hair, and other debris) from a surface to be cleaned and forcollecting the removed debris in a space provided on the vacuum cleanerfor later disposal. Vacuum cleaners are usable on a wide variety ofcommon household surfaces such as soft flooring including carpets andrugs, and hard or bare flooring, including tile, hardwood, laminate,vinyl, and linoleum.

One type of carpet presently gaining in popularity is “super soft” or“ultra-soft” carpet, which is made up of lower denier fibers that aremore densely tufted onto a carpet backing than for conventional carpettypes such as “plush”, “Berber” or “frieze”, for example. Denier is ameasurement of weight; more specifically, denier is the weight in gramsof 9,000 meters of a filament, fiber or yarn. Typically, a thinner fiberwill weigh less and will have a lower denier than a relatively thickerfiber. The denier of a filament of fibers used in a super soft carpettypically ranges from 3.5 to 5, while the nylon filaments of aconventional carpet have a denier of 12 to 18. The combination of lowdenier fibers and dense tufting gives a super soft carpet a very softand plush feel, but can also create difficulties with respect to vacuumcleaning since the densely-packed fibers can impede airflow, which cancause the suction nozzle to suck down and become virtually sealed or“locked down” to the super soft carpet. This nozzle “lock down”condition can increase the push force required to move the vacuumcleaner over the carpet. Additionally, the carpet backing typically usedwith super soft carpet can be nearly impermeable to airflow, which canexacerbate nozzle lock down and further increase the push force.

Although different carpet types can increase a vacuum cleaner's pushforce to varying degrees, other aspects, including the structuralconfiguration of the vacuum cleaner, can increase or compound the pushforce problem. For example, for upright or stick vacuum cleaners thelocation of the connection between the upright or handle portion and thebase portion can transmit a downward component of push force onto thesuction nozzle, which can dig the suction nozzle into the cleaningsurface thereby increasing the push force. Additionally, rough, worn orscuffed vacuum cleaner housings or the presence of tacky or stickymaterial on the surface to be cleaned or on the vacuum cleaner housingscan further increase push force. Moreover, obstacles on the surface,such as area rugs and thresholds, for example, can also impede freemovement of the vacuum cleaner and thus increase push force, at leasttemporarily, until the obstacle is removed or overcome.

BRIEF DESCRIPTION

According to an aspect of the present disclosure a vacuum cleaner has ahousing including an upright unit having a handle operably coupled to abase unit, the base unit including a chassis having a carriage fixed tothe chassis and wheels coupled to the carriage for facilitating movementover a surface to be cleaned, a nozzle unit with a suction nozzle, asuction source in fluid communication with the suction nozzle forgenerating a working airstream, a mechanical linkage coupling the nozzleunit to the carriage of the chassis, wherein the mechanical linkagecomprises at least two degrees of freedom to displace the nozzlerelative to the surface to be cleaned, independently of the chassis,such that the suction nozzle can raise and float relative to the chassiswherein the mechanical linkage is configured to automatically lift thesuction nozzle away from the surface to be cleaned upon a predeterminedforce being applied to the nozzle unit during movement of the base unitacross the surface to be cleaned, and a working air duct forming atleast a portion of the working air path from the suction nozzle to thesuction source, the working air duct adapted for accommodating the floatof the suction nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of a vacuum cleaner according to a firstaspect of the present disclosure.

FIG. 2 is a perspective view of a vacuum cleaner according to a secondaspect of the present disclosure.

FIG. 3 is an exploded view of a base unit of the vacuum cleaner fromFIG. 2.

FIG. 4 is a side view showing the base unit of the vacuum cleaner fromFIG. 2 in a neutral operational position.

FIG. 5 is a side view showing the base unit of the vacuum cleaner fromFIG. 2 in a first raised operational position during a forward stroke ofthe vacuum cleaner.

FIG. 6 is a side view showing the base unit of the vacuum cleaner fromFIG. 2 in a second raised operational position during a rearward strokeof the vacuum cleaner.

FIG. 7 is a perspective view of a vacuum cleaner according to a thirdaspect of the present disclosure.

FIG. 8A is a partially exploded view of a base unit of the vacuumcleaner from FIG. 7.

FIG. 8B is another partially exploded view of a base unit of the vacuumcleaner from FIG. 7.

FIG. 9 is a side view showing the base unit of the vacuum cleaner fromFIG. 7 in a neutral operational position.

FIG. 10 is a side view showing the base unit of the vacuum cleaner fromFIG. 7 in a first raised operational position during a forward stroke ofthe vacuum cleaner.

FIG. 11 is a side view showing the base unit of the vacuum cleaner fromFIG. 7 in a second raised operational position during a rearward strokeof the vacuum cleaner.

FIG. 12 is a schematic view of a vacuum cleaner according to a fourthaspect of the present disclosure.

FIG. 13 is a side view showing the vacuum cleaner from FIG. 12 in afirst raised operational position during a forward stroke of the vacuumcleaner.

FIG. 14 is a side view showing the vacuum cleaner from FIG. 12 in asecond raised operational position during a rearward stroke of thevacuum cleaner.

FIG. 15 is a schematic view of a vacuum cleaner according to a fifthaspect of the present disclosure.

FIG. 16 is a side view showing the vacuum cleaner from FIG. 15 in araised operational position during a forward stroke of the vacuumcleaner.

FIG. 17 is a schematic view of a vacuum cleaner according to a sixthaspect of the present disclosure.

FIG. 18 is a side view showing the vacuum cleaner from FIG. 17 in araised operational position during a forward stroke of the vacuumcleaner.

FIG. 19 is a schematic view of a vacuum cleaner according to a seventhaspect of the present disclosure.

FIG. 20 is a side view showing the vacuum cleaner from FIG. 19 in araised operational position during a forward stroke of the vacuumcleaner.

FIG. 21 is a schematic side view of a vacuum cleaner according to aneighth aspect of the present disclosure.

FIG. 22 is a schematic side view showing the vacuum cleaner from FIG. 21in a first raised operational position during a forward stroke of thevacuum cleaner.

FIG. 23 is a schematic side view showing the vacuum cleaner from FIG. 21in a second raised operational position during a rearward stroke of thevacuum cleaner.

FIG. 24 is a schematic view of a vacuum cleaner according to a ninthaspect of the present disclosure.

FIG. 25 is a side view showing the vacuum cleaner from FIG. 24 in afirst raised operational position during a forward stroke of the vacuumcleaner.

FIG. 26 is a side view showing the vacuum cleaner from FIG. 24 in asecond raised operational position during a rearward stroke of thevacuum cleaner.

FIG. 27 is a schematic view of a vacuum cleaner according to a tenthaspect of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 is a schematic view of various functional systems of a vacuumcleaner 10. The vacuum cleaner 10 may be substantially similar to aconventional vacuum cleaner in that it includes a vacuum collectionsystem 12 for creating a partial vacuum to suck up debris (which mayinclude dirt, dust, soil, hair, and other debris) from a surface to becleaned and collecting the removed debris in a space provided on thevacuum cleaner 10 for later disposal. The vacuum cleaner 10 can beprovided in the form of an upright vacuum cleaner, a hand-held vacuumcleaning device, or as an apparatus having a floor nozzle or a hand-heldaccessory tool connected to a canister or other portable device by avacuum hose or conduit. Additionally, in some aspects of the presentdisclosure the vacuum cleaner 10 can have fluid delivery capability,including applying liquid or steam to the surface to be cleaned, and/orfluid extraction capability.

The vacuum collection system 12 can include a working air path 14through the vacuum cleaner 10, which may include one or more of asuction nozzle 16, a suction source 18 in fluid communication with thesuction nozzle 16 for generating a working airstream, and a separatingand collection assembly 20 for separating and collecting liquid and/ordebris from the working airstream for later disposal. In oneconfiguration illustrated herein, the collection assembly 20 can includea cyclone separator 22 for separating contaminants from a workingairstream and a removable dirt cup 24 for receiving and collecting theseparated contaminants from the cyclone separator 22. The cycloneseparator 22 can have a single cyclonic separation stage, or multiplestages. In another configuration, the collection assembly 20 can includean integrally formed cyclone separator and dirt cup, with the dirt cupbeing provided with a structure, such as a bottom-opening dirt door, forcontaminant disposal. It is understood that other types of collectionassemblies 20 can be used, such as a bulk separator, a filter bag, or awater-bath separator, for example.

The suction source 18, such as a motor/fan assembly, is provided influid communication with the separating and collection assembly 20, andcan be positioned downstream or upstream of the separating andcollection assembly 20. The suction source 18 can be electricallycoupled to a power source 26, such as a battery or by a power cordplugged into a household electrical outlet. A suction power switch 28between the suction source 18 and the power source 26 can be selectivelyclosed by the user upon pressing a vacuum power button (not shown),thereby activating the suction source 18.

The vacuum collection system 12 can also be provided with one or moreadditional filters 30 upstream or downstream of the separating andcollection assembly 20 or the suction source 18. Optionally, an agitator32 can be provided adjacent to the suction nozzle 16 for agitatingdebris on the surface to be cleaned so that the debris is more easilyingested into the suction nozzle 16. Some examples of agitators 32include, but are not limited to, a rotatable brushroll, dual rotatingbrushrolls, or a stationary brush. The agitator 32 can be driven by thesame motor/fan assembly serving as the suction source 18, or mayoptionally be driven by a separate drive assembly, such as a dedicatedagitator motor.

The vacuum cleaner 10 further includes a mechanical linkage 34 couplingat least the suction nozzle 16 of the vacuum cleaner 10 to anotherportion of the vacuum cleaner 10, so that the suction nozzle 16 can moveindependently of the other portion. More specifically, the vacuumcleaner 10 can include a chassis 36, and the mechanical linkage 34 cancouple the suction nozzle 16 to the chassis 36. The mechanical linkage34 can have both a horizontal and a vertical degree of freedom, suchthat the suction nozzle 16 can move both horizontally and vertically,independently of the chassis 36.

The chassis 36 can include at least one wheel 38 for facilitatingmovement of the vacuum cleaner over a surface to be cleaned, andsupports one or more components of the vacuum cleaner 10. Somenon-limiting examples of wheels 38 for the chassis 36 include, but arenot limited to, standard wheels with a center rotating hub or bearing onan axle, casters, and/or hemispherical or spherical wheels. Somenon-limiting examples of chassis components include, but are not limitedto, housings, ducts or conduits forming a portion of working air path14, the suction source 18 itself, the separating and collection assembly20, the filter 30, and/or a handle for maneuvering the vacuum cleaner10.

The suction nozzle 16 can be included with a nozzle unit 40 that movesrelative to the chassis 36. The entire nozzle unit 40 can be coupledwith the chassis 36 via the mechanical linkage 34, and can support oneor more components of the vacuum cleaner 10 in addition to the suctionnozzle 16. Some non-limiting examples of nozzle unit components include,but are not limited to, the agitator 32, an agitator motor or otherdrive assembly for the agitator, ducts or conduits forming a portion ofworking air path 14, the suction source 18 itself, the separating andcollection assembly 20, and/or the filter 30.

In one example, the vacuum cleaner 10 can be an upright-type vacuumcleaner, in which an upper upright unit 42 having a handle 44 ispivotally mounted to a lower base unit 46 which moves over the surfaceto be cleaned. The chassis 36 may include the upright unit 42 as well asa portion of the base unit 46. The nozzle unit 40 may be coupled to theportion of the base unit 46 via the mechanical linkage 34. A pivotconnection 48, including, but not limited to, a universal joint, can beprovided between the upright unit 42 and the base unit 46.

The components of the vacuum cleaner 10 can be housed or carried on theupright unit 42 or base unit 46 in various combinations. For example,the suction source 18 and collection assembly 20 can be provided on theupright unit 42, while the suction nozzle 16, agitator 32, and optionalagitator drive assembly can be provided on the base unit 46.

The vacuum cleaner 10 shown in FIG. 1 can be used to effectively clean asurface by removing debris (which may include dirt, dust, soil, hair,and other debris) from the surface in accordance with the followingmethod. The sequence of steps discussed is for illustrative purposesonly and is not meant to limit the method in any way as it is understoodthat the steps may proceed in a different logical order, additional orintervening steps may be included, or described steps may be dividedinto multiple steps, without detracting from the present disclosure.

To perform vacuum cleaning, the suction source 18 is coupled to thepower source 26. The suction nozzle 16 is moved over the surface to becleaned, generally in a series of forward and backward strokes. Thesuction source 18 draws in debris-laden air through the suction nozzle16 and into the separating and collection assembly 20 where the debrisis substantially separated from the working air. The air flow thenpasses the suction source 18, and through any optional filters 30, priorto being exhausted from the vacuum cleaner 10. During vacuum cleaning,the agitator 32 can agitate debris on the surface so that the debris ismore easily ingested into the suction nozzle 16. The separating andcollection assembly 20 can be periodically emptied of debris. Likewise,the optional filters 30 can periodically be cleaned or replaced.

In one specific operation, the vacuum cleaner 10 of FIG. 1 may be usedto clean a super soft carpet 50 having carpet fibers 52 on a carpetbacking 54. Vacuuming super soft carpet 50 can prove challenging sincethe densely-packed fibers 52 and carpet backing 54 can impede airflowand increase the push force required to move the vacuum cleaner 10 overthe carpet 50. Indeed, the suction nozzle 16 can become virtually sealedor “locked” onto the carpet 50, preventing a user from easily moving thevacuum cleaner 10 across the carpet 50. To reduce or eliminate the“lock-down” issue, the mechanical linkage 34 coupling the suction nozzle16 to the chassis 36 has at least two degrees of freedom, including ahorizontal degree of freedom and a vertical degree of freedom, where“horizontal” and “vertical” and variations thereof, with respect to themechanical linkage 34, are relative to the carpet 50.

The mechanical linkage 34 can be actuated upon a predetermined amount offorce or resistance being applied to the suction nozzle 16, or nozzleunit 40, on a forward or backward stroke of the vacuum cleaner 10. On aforward or rearward stroke, the suction nozzle 16 may remain in a normaloperation position with respect to the carpet 50. Upon the predeterminedamount of resistance being applied, such as from lock-down or frictionfor example, the mechanical linkage 34 is configured to lift the suctionnozzle 16 away from the carpet 50. The resistance caused by frictionbetween the suction nozzle 16, or nozzle unit 40 sliding on a surface tobe cleaned, also referred to as ‘friction force’, is proportional to thecoefficient of friction between the suction nozzle 16 and surface to becleaned and the and the normal force of the vacuum cleaner 10 upon thesurface to be cleaned. The magnitude of the normal force can beincreased or decreased depending on the weight and the suction force ofthe vacuum cleaner 10. The coefficient of friction between the vacuumcleaner 10 and the surface to be cleaned can be increased or decreaseddepending on the type and properties of the surface to be cleaned, suchas carpet type and denier of the carpet fibers, as well as the conditionof the components of the cleaner 10 in contact with the surface. Forexample, scuffed vacuum cleaner housings or dense, thick carpet canincrease coefficient of friction. The push force is equal to thecoefficient of friction multiplied by the normal force. Thus, becausethe mechanical linkage 34 lifts the suction nozzle 16 upwardly byapplying an upward force, the linkage 34 also has the effect of reducingthe net normal force, which also reduces the push force. Other sourcesof resistance may include encountering a threshold or transitioning froma bare floor to carpet. During operation, the suction nozzle 16 may besubjected to resistance at levels less than the predetermined amount andthe mechanical linkage 34 will not be actuated. In one example, thepredetermined amount of resistance can be greater than the weight of thenozzle unit 40.

The mechanical linkage 34 can be configured such that horizontal motionof the chassis 36, i.e. movement across the carpet 50 on a forward orbackward stroke, is convertible into vertical displacement of thesuction nozzle 16. During normal operation, the nozzle unit 40 may movetogether with the chassis 36. However, when the nozzle unit 40encounters the predetermined amount of resistance during a forward orbackward stroke, such as from lock-down for example, the movement of thenozzle unit 40 may be arrested while the chassis 36 continues to movehorizontally. Thus, the nozzle unit 40 is horizontally displacedrelative to the chassis 36. The mechanical linkage 34 further convertsthe resistance force to vertical displacement of the nozzle unit 40, andthe suction nozzle 16 is forced upwardly, rather than sucking down andsealing to the carpet 50. As the horizontal resistance decreases, thesuction nozzle 16 can automatically lower towards the carpet 50. Forexample, when the weight of the nozzle unit 40 overcomes the horizontalresistance, the nozzle unit 40 can lower to its normal operationalposition.

FIGS. 2-23 show several examples of mechanical linkages for vacuumcleaners. Many of the components of the vacuum cleaners that are notdirectly germane to the mechanical linkage are not discussed in detailin FIGS. 2-23, but rather are understood to be incorporated in theexamples from the description of FIG. 1.

FIG. 2 is a perspective view of a vacuum cleaner 60 according to asecond aspect of the present disclosure. The vacuum cleaner 60 includesa chassis 62, a suction nozzle 64, and a mechanical linkage 66 formoving the suction nozzle 64 relative to the chassis 62. In the presentexample, the vacuum cleaner 60 is an upright-type vacuum cleaner, inwhich an upright unit 68 having a handle 70 and supporting a separatingand collection assembly 72 is pivotally mounted to a base unit 74, whichmoves over the surface to be cleaned. A pivot connection 76, including,but not limited to, a universal joint, can be provided between theupright unit 68 and the base unit 74. The chassis 62 may include theupright unit 68 as well as a portion of the base unit 74. In the presentexample, the suction nozzle 64 is defined by a nozzle unit 78, and theentire nozzle unit 78 may be coupled to the portion of the base unit 74forming the chassis 62 via the mechanical linkage 66.

FIG. 3 is an exploded view of the base unit 74 of FIG. 2. The base unit74 includes a chassis portion 80 coupled to the nozzle unit 78 by themechanical linkage 66. The nozzle unit 78 includes a housing 86 thatdefines a partially enclosed space for housing, carrying, or definingseveral components, including the suction nozzle 64, a motor/fanassembly 82, and an agitator 84. As shown herein, the housing 86includes an upper member including a suction chamber 88 and an uppermotor casing 90, a sole plate 92 coupled to the suction chamber 88, anda lower motor casing 94 coupled to the upper motor casing 90. Otherconfigurations of the housing 86 are also possible.

The motor/fan assembly 82 is held between the upper and lower motorcasings 90, 94, and can provide suction force at suction nozzle 64 aswell as drive force for the agitator 84. The suction nozzle 64 isdefined by the suction chamber 88 and a suction nozzle opening 96 formedin the sole plate 92 in fluid communication with the suction chamber 88.The suction chamber 88 fluidly communicates the suction nozzle opening96 with the separating and collection assembly 72 (FIG. 2).

The agitator 84 is secured within the suction chamber 88 by the soleplate 92, and can be coupled to the motor/fan assembly 82 for rotationalmovement via a drive belt 98. The agitator 84 is illustrated as arotatable brushroll; however, it is within the scope of the presentdisclosure for other types of agitators to be used, such as a stationarybrush or dual rotating brushrolls.

The agitator 84 illustrated herein includes a generally cylindricalbrush dowel 100 that communicates with the belt 98, with a bearing 102on both ends facilitating rotation of the dowel 100 within the suctionchamber 88. A plurality of bristle tufts 104 project or extend from theouter circumference of the dowel 100. Each bristle tuft 104 can includea plurality of flexible bristles, which may be made from a durablepolymer material such as nylon or polyester, for example.

The chassis portion 80 includes a carriage 106 having a set of rearwheels 108 and a set of front wheels 110 for maneuvering the base unit74 over a surface to be cleaned. The carriage 106 includes a platform112 extending beneath the lower motor housing 94 and having a wheelmount 114 provided at the rear of the platform 112 for supporting therear wheels 108 and a wheelhouse 116 provided at the front of theplatform 112 for partially surrounding the front wheels 110. The rearwheels 108 are mounted to the wheel mount 114 by rear wheel axles 118secured by clips 120, and the front wheels 110 are mounted within thewheelhouses 116 by front wheel axles 122 secured by clips 124.

The mechanical linkage 66 of the second example includes a four-barlinkage. The four bodies making up the four-bar linkage include thehousing 86 of the nozzle unit 78, the carriage 106 of the chassisportion 80, a rear link 126, and a front link 128 connected in a loop byjoints, with the front and rear links 126, 128 joining the carriage 106and the housing 86. As shown, a mirror image set of four-bar linkagesare provided, and laterally spaced on either side of the base unit 74.

The joint connecting the housing 86 to the rear link 126 is a revolutejoint having one degree of freedom. The revolute joint is formed by anaxle 130 extending from the housing 86 and a bearing surface 132 on anupper end of the rear link 126. In the present example the axle 130 isprovided on the lower motor casing 94, and is collinear with thehorizontal axis of the motor/fan assembly 82 defined by a drive shaft134, although in other configurations the axle 130 may be offset fromthe axis.

The joint connecting the carriage 106 to the rear link 126 is a revolutejoint having one degree of freedom. The revolute joint is formed by anaxle in the form of a shaft pin 134 mounted within a bore 136 extendingthrough the carriage 106 and a bearing surface 138 on a lower end of therear link 126. In the present example the shaft pin 134 is held in afixed position relative to the carriage 106 by a clip 140. The carriage106 includes a stop 152 for limiting the forward rotation of the rearlink 126 about the shaft pin 134.

The joint connecting the carriage 106 to the front link 128 is arevolute joint having one degree of freedom. The revolute joint isformed by the front wheel axle 122 mounted within the wheelhouse 116 anda bearing surface 142 on the lower end of the front link 128.

The joint connecting the housing 86 to the rear link 126 is apin-in-slot joint having two degrees of freedom. The pin-in-slot jointis formed by an axle in the form of a shaft pin 144 mounted within abore 146 of the housing 86 and a slot 148 on an upper end of the frontlink 128. In the present example the bore 146 is provided on the uppermember of the housing 86 and the shaft pin 144 is held in a fixedposition relative to the upper member by a clip 150.

To accommodate for the movement of the motor/fan assembly 82 relative tothe chassis 62, the vacuum cleaner 60 can be provided with a firstworking air duct 154 between the nozzle unit 78 and the separating andcollection assembly 72 and a second working air duct 156 between theseparating and collection assembly 72 and the motor/fan assembly 82 thatare flexible, pivotable, or otherwise have sufficient clearance formovement of the nozzle unit 78 relative to the chassis 62. As shownherein at least a portion of the working air ducts 154, 156 include aflexible hose segment.

FIGS. 4-6 are side views showing the base unit 74 in various operationalpositions. FIG. 4 shows the base unit 74 in a neutral operationalposition; the base unit 74 may be in the neutral operational positionwhen the resistance on the nozzle unit 78 is below a predeterminedamount. For example, the resistance on the nozzle unit 78 in FIG. 4,whether the base unit 74 is moving forward or backward over the surfaceto be cleaned, can be less than or equal to the weight of the nozzleunit 78. In the neutral operational position, the suction nozzle 64 islowered to the surface to be cleaned.

FIG. 5 shows a first raised operational position of the nozzle unit 78during a forward stroke of the base unit 74. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 78 inan opposing direction to the direction of movement of the base unit 74,the mechanical linkage 66 lifts the suction nozzle 64 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 64, while the carriage 106 continues forward, and the carriage106 acts as a ground link or frame about which the front link 128 isforced to pivot. The movement of the front link 128 is transmitted tothe rear link 126 via the housing 86, which acts as a floating link orcoupler between the grounded front and rear links 128, 126. As thecarriage 106 moves forward, the links 128, 126 pivot rearwardly, and theentire nozzle unit 78, including the suction nozzle 64, is raised andpivots about axle 130. In the raised position, the suction nozzle 64 isboth vertically and horizontally displaced with respect to the neutraloperational position. The horizontal displacement results in the suctionnozzle 64 being horizontally closer to the carriage 106.

FIG. 6 shows a second raised operational position of the nozzle unit 78during a rearward stroke of the base unit 74. On a rearward stroke, if apredetermined amount of resistance is applied to the nozzle unit 78 inan opposing direction to the direction of movement of the base unit 74,the mechanical linkage 66 lifts the suction nozzle 64 away from thesurface. Specifically, the resistance, such as an obstacle 158 like theedge of an area rug or a threshold for example, as shown in FIG. 6,arrests movement of the suction nozzle 64, while the carriage 106continues rearwardly, the slot 148 in the front link 128 slides relativeto the pin 144 and the suction nozzle 64 pivots about axle 130 as itslides over the obstacle 158, thereby raising the entire nozzle unit 78.In the raised position, the suction nozzle 64 is both vertically andhorizontally displaced with respect to the neutral operational position.The horizontal displacement results in the suction nozzle 64 beinghorizontally further from the carriage 106.

FIG. 7 is a perspective view of a vacuum cleaner 160 according to athird aspect of the present disclosure. The vacuum cleaner 160 includesa chassis 162, a suction nozzle 164, and a mechanical linkage 166 formoving the suction nozzle 164 relative to the chassis 162. In thepresent example, the vacuum cleaner 160 is an upright-type vacuumcleaner, in which an upright unit 168 having a handle 170 and supportinga separating and collection assembly 172 is pivotally mounted to a baseunit 174, which moves over the surface to be cleaned. A pivot connection176 can be provided between the upright unit 168 and the base unit 174.The chassis 162 may include the upright unit 168 as well as a portion ofthe base unit 174. In the present example, the suction nozzle 164 isdefined by a nozzle unit 178, and the entire nozzle unit 178 may becoupled to the portion of the base unit 174 forming the chassis 162 viathe mechanical linkage 166. The third example further includes amotor/fan assembly 180 in the upright unit 168 which can provide suctionforce at suction nozzle 164 and is in fluid communication with theseparating and collection assembly 172.

FIG. 8A is a partially exploded view of the base unit 174 of FIG. 7. Thebase unit 174 includes a chassis portion 182 coupled to the nozzle unit178 by the mechanical linkage 166. The nozzle unit 178 includes ahousing that defines a partially enclosed space for housing, carrying,or defining several components, including the suction nozzle 164, anagitator 186, and an agitator motor 188. As shown herein, the housingincludes an upper member 190 with a suction chamber 192 and a motor seat194, a lower member 196 including a sole plate 198 coupled to thesuction chamber 192, and a cover 200 coupled to the upper member 190.Other configurations of the housing are also possible.

The suction nozzle 164 is defined by the suction chamber 192 and asuction nozzle opening 202 formed in the sole plate 198 in fluidcommunication with the suction chamber 192. The suction chamber 192fluidly communicates the suction nozzle opening 202 with a working airduct formed by mating upper and lower duct halves 204, 206, which can becoupled with a flexible hose 207 in fluid communication with thecollection system 172 (FIG. 7).

The agitator motor 188 is held in the motor seat 194 between the uppermember 190 and the cover 200, and can provide drive force for theagitator 186. The agitator 186 is secured within the suction chamber 192by the sole plate 198, and can be coupled to the agitator motor 188 forrotational movement via a drive belt 208. The agitator 186 isillustrated as a rotatable brushroll; however, it is within the scope ofthe present disclosure for other types of agitators to be used, such asa stationary brush or dual rotating brushrolls.

The agitator 186 includes a generally cylindrical brush dowel 210 thatcommunicates with the belt 208, with a bearing 212 on both endsfacilitating rotation of the dowel 210 within the suction chamber 192. Aplurality of bristle tufts 214 project or extend from the outercircumference of the dowel 210. Each bristle tuft 214 can include aplurality of flexible bristles, which may be made from a durable polymermaterial such as nylon or polyester, for example.

FIG. 8B is another partially exploded view of the base unit 174 of FIG.7. The chassis portion 182 includes a carriage 216 having a set of rearwheels 218 and a set of front wheels 220 for maneuvering the base unit174 over a surface to be cleaned. The carriage 216 includes a platform222 extending beneath the lower member 196 and having two outwardlyextending arms 224, each arm 224 having a wheelhouse 226 provided at thefront of the platform 222 for partially surrounding the front wheels 220and a wheel mount 228 provided at the rear of the platform 222 forsupporting the rear wheels 218. The rear wheels 218 are mounted onbushings 230 to the wheel mount 228 by hubs 232, and the front wheels220 are mounted within the wheelhouses 226 by front wheel axles 234secured by clips 236.

The pivot connection 176 coupling the upright unit 168 (FIG. 7) to thechassis portion 182 of the base unit 174 includes a yoke 238 straddlingthe working air duct 204, 206 and having oppositely-extending shaft pins240 defining a first axis of rotation and a central coupler 242 defininga second axis of rotation. The shaft pins 240 are received in bearings244 on the inner sides of the wheel mount 228 provided on the carriage216. The central coupler 242 is rotatably coupled with a lower portionof the upright unit 168 (FIG. 7).

The mechanical linkage 166 of the third example includes a cam jointthat controls the position of the nozzle unit 178 relative to thechassis portion 182 and a pin-in-slot joint that limits the movement ofthe nozzle unit 178 relative to the chassis portion 182. The cam jointincludes a cam 250 provided on the nozzle unit 178 and a cam follower252 provided on the chassis portion 182. As shown, the cam 250 isprovided on the upper member 190 in the form of a double wedge. Thedouble wedge cam 250 includes a front wedge 254 and a rear wedge 256joined at a vertex 258, together forming an inverted V-shaped track 260defining a path for the cam follower 252 that includes both horizontaland vertical components of movement. The front end of the track 260 hasa downturn forming a stop 262 for the cam follower 252 and to preventthe nozzle unit 178 from dislodging from the chassis portion 182. Thecam follower 252 is provided as a roller 264 mounted within thewheelhouse 226, above the front wheel 220, by a roller axle 266. Theroller 264 engages and moves along the track 260 defined by the doublewedge cam 250.

The pin-in-slot joint has two degrees of freedom and is formed by theshaft pins 240 extending from the pivot yoke 238 and slots 268 on thenozzle unit 178 that receive the shaft pins 240. In the present examplethe slots 268 are provided on arms 270 extending rearwardly from theupper member 190 (FIG. 8A), on either side of the upper duct 204.

FIGS. 9-11 are side views showing the base unit 174 in variousoperational positions. FIG. 9 shows the base unit 174 in a neutraloperational position; the base unit 174 may be in the neutraloperational position when the resistance on the nozzle unit 178 is belowa predetermined amount. For example, the resistance on the nozzle unit178 in FIG. 9, whether the base unit 174 is moving forward or backwardover the surface to be cleaned, can be less than or equal to the weightof the nozzle unit 178. In the neutral operational position, the roller264 rests in the vertex 258 of the cam 250 and the suction nozzle 164 islowered to the surface to be cleaned.

FIG. 10 shows a first raised operational position of the nozzle unit 178during a forward stroke of the base unit 174. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 178 inan opposing direction to the direction of movement of the base unit 174,the mechanical linkage 166 lifts the suction nozzle 164 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 164, while the carriage 216 continues forward. The roller 264follows the front portion of the track 260 defined by the front wedge254, thereby lifting the entire nozzle portion 178. The movement of thenozzle portion 178 can be stopped by the pin 240 reaching the front endof the slot 268, as well as by the stop 262 on the cam 250. In theraised position, the suction nozzle 164 is both vertically andhorizontally displaced with respect to the neutral operational position.The horizontal displacement results in the suction nozzle 164 beinghorizontally closer to the carriage 216.

FIG. 11 shows a second raised operational position of the nozzle unit178 during a rearward stroke of the base unit 174. On a rearward stroke,if a predetermined amount of resistance is applied to the nozzle unit178 in an opposing direction to the direction of movement of the baseunit 174, such as from an obstacle 158 as shown or from nozzle lock-downregardless of whether an obstacle 158 is present, the mechanical linkage166 lifts the suction nozzle 164 away from the surface. Specifically,the resistance arrests movement of the suction nozzle 164, while thecarriage 216 continues backward. The roller 264 follows the rear portionof the track 260 defined by the rear wedge 256, thereby lifting theentire nozzle portion 178. The movement of the nozzle portion 178 can bestopped by the pin 240 reaching the rear end of the slot 268. In theraised position, the suction nozzle 164 is both vertically andhorizontally displaced with respect to the neutral operational position.The horizontal displacement results in the suction nozzle 164 beinghorizontally further from the carriage 216.

FIG. 12 is a schematic view of a vacuum cleaner 280 according to afourth aspect of the present disclosure. The vacuum cleaner 280 includesa chassis 282, a suction nozzle 284, and a mechanical linkage 286 formoving the suction nozzle 284 relative to the chassis 282. In thepresent example, the vacuum cleaner 280 is schematically illustrated asan upright-type vacuum cleaner, in which in which an upright unit 288having a handle 290 is pivotally mounted to a base unit 292, which movesover the surface to be cleaned. A pivot connection 294, including, butnot limited to, a universal joint, can be provided between the uprightunit 288 and the base unit 292. The chassis 282 may include the uprightunit 288 as well as a portion of the base unit 292. Many of thecomponents of the vacuum cleaner 280 that are not directly germane tothe mechanical linkage 286 are not shown for purposes of simplification,but rather are understood to be incorporated in the examples from thedescription of FIG. 1; such components may include, but are not limitedto, a separating and collection assembly, a suction source, and/or anagitator drive assembly.

The base unit 292 includes a chassis portion 296 coupled to the suctionnozzle 284 by the mechanical linkage 286. The chassis portion 296includes a carriage 298 having a set of rear wheels 300 and a set offront wheels 302 for maneuvering the base unit 292 over a surface to becleaned.

The suction nozzle 284 is defined by a nozzle unit 304, and the entirenozzle unit 304 may be coupled to the carriage 298 via the mechanicallinkage 286. The nozzle unit 304 includes a housing 306 that defines apartially enclosed space for housing, carrying, or defining severalcomponents, including the suction nozzle 284 and an agitator 308. Theagitator 308 is illustrated as a rotatable brushroll; however, it iswithin the scope of the present disclosure for other types of agitatorsto be used, such as a stationary brush or dual rotating brushrolls.

The mechanical linkage 286 of the fourth example includes a four-barlinkage from which the nozzle unit 304 hangs or is suspended. The fourbodies making up the four-bar linkage include a supporting body 310supporting the nozzle unit 304, the carriage 298, a rear link 312, and afront link 314 connected in a loop by joints, with the links 312, 314joining the carriage 298 and the supporting body 310. In the presentexample, joints 316, 318 connect the carriage 298 to the rear link 312and the front link 314, respectively, and can be collinear with therotational axes of the wheels 300, 302, although in other configurationsthe joints 316, 318 may be offset from the rotational axes. Joints 320,322 connect the supporting body 310 to the rear link 312 and the fontlink 314, respectively. The joints can be revolute joints having onedegree of freedom. While not shown in FIG. 12, a pair of four-barlinkages may be provided, and laterally spaced on either side of thebase unit 292, in a similar manner as described for the second examplein FIG. 2.

FIGS. 12-14 show the base unit 292 in various operational positions.FIG. 12 shows the base unit 292 in a neutral operational position; thebase unit 292 may be in the neutral operational position when theresistance on the nozzle unit 304 is below a predetermined amount. Forexample, the resistance on the nozzle unit 304 in FIG. 12, whether thebase unit 292 is moving forward or backward over the surface to becleaned, can be less than or equal to the weight of the nozzle unit 304.In the neutral operational position, the suction nozzle 284 is loweredto the surface to be cleaned.

FIG. 13 shows a first raised operational position of the nozzle unit 304during a forward stroke of the base unit 292. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 304 inan opposing direction to the direction of movement of the base unit 292,the mechanical linkage 286 lifts the suction nozzle 284 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 284, while the chassis 282 continues forward, and the carriage298 acts as a ground link or frame about which the front link 314 ispivoted. The movement of the front link 314 is transmitted to the rearlink 312 via the supporting body 310, which acts as a floating link orcoupler between the grounded front and rear links 312, 314. As the links312, 314 pivot rearwardly, the supporting body 310 floats upwardly andrearwardly and the entire nozzle unit 304 is raised. In the raisedposition, the suction nozzle 284 is both vertically and horizontallydisplaced with respect to the neutral operational position. Thehorizontal displacement results in the suction nozzle 284 beinghorizontally closer to the carriage 298.

FIG. 14 shows a second raised operational position of the nozzle unit304 during a rearward stroke of the base unit 292. On a rearward stroke,if a predetermined amount of resistance is applied to the nozzle unit304 in an opposing direction to the direction of movement of the baseunit 292, such as from an obstacle 158 as shown or from nozzle lock-downregardless of whether an obstacle 158 is present, the mechanical linkage286 lifts the suction nozzle 284 away from the surface. Specifically,the resistance arrests movement of the suction nozzle 284, while thechassis 282 continues rearward, and the links 312, 314 pivot forwardlyto move the supporting body 310 upwardly and forwardly, thereby raisingthe entire nozzle unit 304. In the raised position, the suction nozzle284 is both vertically and horizontally displaced with respect to theneutral operational position. The horizontal displacement results in thesuction nozzle 284 being horizontally further from the carriage 298.

FIG. 15 is a schematic view of a vacuum cleaner 330 according to a fifthaspect of the present disclosure. The vacuum cleaner 330 includes achassis 332, a suction nozzle 334, and a mechanical linkage 336 formoving the suction nozzle 334 relative to the chassis 332. In thepresent example, the vacuum cleaner 330 is schematically illustrated asan upright-type vacuum cleaner, in which in which an upright unit 338having a handle 340 is pivotally mounted to a base unit 342, which movesover the surface to be cleaned. A pivot connection 344, including, butnot limited to, a universal joint, can be provided between the uprightunit 338 and the base unit 342. The chassis 332 may include the uprightunit 338 as well as a portion of the base unit 342. Many of thecomponents of the vacuum cleaner 330 that are not directly germane tothe mechanical linkage 336 are not shown for purposes of simplification,but rather are understood to be incorporated in the examples from thedescription of FIG. 1; such components may include, but are not limitedto, a separating and collection assembly and/or an agitator driveassembly.

The base unit 342 includes a chassis portion 346 coupled to the suctionnozzle 334 by the mechanical linkage 336. The chassis portion 346includes a carriage 348 having a rear skid plate 350 and a set of frontwheels 352 for maneuvering the base unit 342 over a surface to becleaned. Alternatively, rear wheels can be used on the rear of thecarriage 348 instead of the skid plate 350. A motor/fan assembly 360provided on the chassis portion 346 can provide suction force at suctionnozzle 334.

The suction nozzle 334 is defined by a nozzle unit 354, and the entirenozzle unit 354 may be coupled to the carriage 348 via the mechanicallinkage 336. The nozzle unit 354 includes a housing 356 that defines apartially enclosed space for housing, carrying, or defining severalcomponents, including the suction nozzle 334 and an agitator 358. Theagitator 358 is illustrated as a rotatable brushroll; however, it iswithin the scope of the present disclosure for other types of agitatorsto be used, such as a stationary brush or dual rotating brushrolls.

The mechanical linkage 336 of the fifth example includes a pivot linkagefrom which the nozzle unit 354 hangs or is suspended. The bodies makingup the pivot linkage include a supporting body 362 supporting the nozzleunit 354 and a link 364 suspending the supporting body 362 from thecarriage 348. An upper joint 366 connects the link 364 to the carriage348 and a lower joint 368 connects the link 364 to the supporting body362. The joints 366, 368 can be revolute joints having one degree offreedom. The upper joint 366 can be collinear with the rotational axisof the wheels 352, although in other configurations the joint 366 may beoffset from the rotational axis.

The nozzle unit 354 is supported at a forward end of supporting body362, and the motor/fan assembly 360 can be provided on the carriage 348on the opposite side of the link 364 as the nozzle unit 354 so that itcounterbalances weight of the nozzle unit 354. While only shownschematically in FIG. 15, the supporting body 362 may be defined by ahousing or casing coupled with the nozzle unit 354, such that thesupporting body 362 can define a partially enclosed space for housing,carrying, or defining components of the nozzle unit 354, such as anagitator drive assembly. Also, while not shown in FIG. 15, a pair ofpivot linkages may be provided, and laterally spaced on either side ofthe base unit 342, in a similar manner as described for the secondexample in FIG. 2.

FIGS. 15-16 show the base unit 342 in various operational positions.FIG. 15 shows the base unit 342 in a neutral operational position; thebase unit 342 may be in the neutral operational position when theresistance on the nozzle unit 354 is below a predetermined amount. Forexample, the resistance on the nozzle unit 354 in FIG. 15, whether thebase unit 342 is moving forward or backward over the surface to becleaned, can be less than or equal to the weight of the nozzle unit 354.In the neutral operational position, the suction nozzle 334 is loweredto the surface to be cleaned.

FIG. 16 shows a raised operational position of the nozzle unit 354during a forward stroke of the base unit 342. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 354 inan opposing direction to the direction of movement of the base unit 342,the mechanical linkage 336 lifts the suction nozzle 334 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 334, while the chassis 332 continues forward, and the carriage348 acts as a ground link or frame about which the link 364 is pivoted.The movement of the link 364 is transmitted to the supporting body 362,which moves upwardly and rearwardly, thereby raising the entire nozzleunit 354. In the raised position, the suction nozzle 334 is bothvertically and horizontally displaced with respect to the neutraloperational position. The horizontal displacement results in the suctionnozzle 334 being horizontally closer to the carriage 348.

FIG. 17 is a schematic view of a vacuum cleaner 380 according to a sixthaspect of the present disclosure. The vacuum cleaner 380 includes achassis 382, a suction nozzle 384, and a mechanical linkage 386 formoving the suction 384 relative to the chassis 382. In the presentexample, the vacuum cleaner 380 is schematically illustrated as anupright-type vacuum cleaner, in which in which an upright unit 388having a handle 390 is pivotally mounted to a base unit 392, which movesover the surface to be cleaned. A pivot connection (not shown),including, but not limited to, a universal joint, can be providedbetween the upright unit 388 and the base unit 392. The chassis 382 mayinclude the upright unit 388 as well as a portion of the base unit 392.Many of the components of the vacuum cleaner 380 that are not directlygermane to the mechanical linkage 386 are not shown for purposes ofsimplification, but rather are understood to be incorporated in theexamples from the description of FIG. 1; such components may include,but are not limited to, a separating and collection assembly and/or asuction source.

The base unit 392 includes a chassis portion 394 coupled to the suctionnozzle 384 by the mechanical linkage 386. The chassis portion 394includes a carriage 396 having a set of rear wheels 398 and a set offront wheels 400 for maneuvering the base unit 392 over a surface to becleaned.

The suction nozzle 384 is defined by a nozzle unit 402, and the entirenozzle unit 402 may be coupled to the carriage 396 via the mechanicallinkage 386. The nozzle unit 402 includes a housing 404 that defines apartially enclosed space for housing, carrying, or defining severalcomponents, including the suction nozzle 384 and an agitator 406. Theagitator 406 is illustrated as a rotatable brushroll; however, it iswithin the scope of the present disclosure for other types of agitatorsto be used, such as a stationary brush or dual rotating brushrolls. Anagitator motor 408 provided on the nozzle unit 402 can provide the driveforce for the agitator 406.

The mechanical linkage 386 of the sixth example includes a pivot linkagethat controls the position of the nozzle unit 402 relative to thechassis portion 394 and a pin-in-slot joint that that limits themovement of the nozzle unit 402 relative to the chassis portion 394. Thebodies making up the pivot linkage include a supporting body 410supporting the nozzle unit 402 and a link 412 connecting the supportingbody 410 to the carriage 396. An upper joint 414 connects the link 412to the supporting body 410 and a lower joint 416 connects the link 412to the carriage 396. The joints 414, 416 can be revolute joints havingone degree of freedom. The lower joint 416 can be collinear with therotational axis of the front wheels 400, although in otherconfigurations the joint 416 may be offset from the rotational axis.

The pin-in-slot joint has two degrees of freedom and is formed by a pin418 extending from the chassis portion 394 and a slot 420 on the nozzleunit 402 that receives the pin 418. In the present example the pin 418can be collinear with the rotational axis of the rear wheels 398,although in other configurations the pin 418 may be offset from therotational axis. The slot 420 can be formed on a rear end of thesupporting body 410, and the nozzle unit 402 can be supported at aforward end of supporting body 410.

While only shown schematically in FIG. 17, the supporting body 410 maybe defined by a housing or casing coupled with the nozzle unit 402, suchthat the supporting body 410 can define a partially enclosed space forhousing, carrying, or defining components of the nozzle unit 402, suchas the agitator motor 408. Also, while not shown in FIG. 17, a pair ofpivot linkages may be provided, and laterally spaced on either side ofthe base unit 392, in a similar manner as described for the secondexample in FIG. 2.

FIGS. 17-18 show the base unit 392 in various operational positions.FIG. 17 shows the base unit 392 in a neutral operational position; thebase unit 392 may be in the neutral operational position when theresistance on the nozzle unit 402 is below a predetermined amount. Forexample, the resistance on the nozzle unit 402 in FIG. 17, whether thebase unit 392 is moving forward or backward over the surface to becleaned, can be less than or equal to the weight of the nozzle unit 402.In the neutral operational position, the suction nozzle 384 is loweredto the surface to be cleaned.

FIG. 18 shows a raised operational position of the nozzle unit 402during a forward stroke of the base unit 392. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 402 inan opposing direction to the direction of movement of the base unit 392,the mechanical linkage 386 lifts the suction nozzle 384 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 384, while the chassis 382 continues forward, and the carriage396 acts as a ground link or frame about which the link 412 is pivoted.The movement of the link 412 is transmitted to the supporting body 410,which moves upwardly and rearwardly, thereby raising the entire nozzleunit 354, including the suction nozzle 384, the agitator 406, and theagitator motor 408. The slot 420 on the supporting body 410 slidesrelative to the pin 418 to allow the suction nozzle 384 to sliderearwardly while simultaneously pivoting about pin 418. The movement ofthe suction nozzle 384 can be stopped by the pin 418 reaching the frontend of the slot 420 on a forward stroke and by reaching the rear end ofthe slot 420 on a rearward stroke. In the raised position, the suctionnozzle 384 is both vertically and horizontally displaced with respect tothe neutral operational position. The horizontal displacement results inthe suction nozzle 384 being horizontally closer to the carriage 396.

FIG. 19 is a schematic view of a vacuum cleaner 430 according to aseventh aspect of the present disclosure. The vacuum cleaner 430includes a chassis 432, a suction nozzle 434, and a mechanical linkage436 for moving the suction nozzle 434 relative to the chassis 432. Inthe present example, the vacuum cleaner 430 is schematically illustratedas an upright-type vacuum cleaner, in which in which an upright unit438, having a handle 440 and supporting a separating and collectionassembly 442, is pivotally mounted to a base unit 444, which moves overthe surface to be cleaned. A pivot connection 446, including, but notlimited to, a universal joint, can be provided between the upright unit438 and the base unit 444. The chassis 432 may include the upright unit438 as well as a portion of the base unit 444. Many of the components ofthe vacuum cleaner 430 that are not directly germane to the mechanicallinkage 436 are not shown for purposes of simplification, but rather areunderstood to be incorporated in the examples from the description ofFIG. 1.

The base unit 444 includes a chassis portion 448 coupled to the suctionnozzle 434 by the mechanical linkage 436. The chassis portion 448includes a carriage 450 having a set of rear wheels 452 and a set offront wheels 454 for maneuvering the base unit 444 over a surface to becleaned. The rotational axis of the rear wheels 452 can be collinearwith the pivot axis of the pivot connection 446, although in otherconfigurations the pivot axis may be offset from the rotational axes.

The suction nozzle 434 is defined by a nozzle unit 456, and the entirenozzle unit 456 may be coupled to the carriage 450 via the mechanicallinkage 436. The nozzle unit 456 includes a housing 458 that defines apartially enclosed space for housing, carrying, or defining severalcomponents, including the suction nozzle 434 and an agitator 460. Theagitator 460 is illustrated as a rotatable brushroll; however, it iswithin the scope of the present disclosure for other types of agitatorsto be used, such as a stationary brush or dual rotating brushrolls.

A motor/fan assembly 462 provided on the base unit 444 can providesuction force at suction nozzle 434 as well as drive force for theagitator 460. The motor/fan assembly 462 can be coupled with theagitator 460 via a conventional drive coupling, such as a drive belt(not shown), and can be provided with the nozzle unit 456. As such, thedistance from the motor/fan assembly 462 the agitator 460 can remainconstant, regardless of the position of the mechanical linkage 436 orthe movement of the nozzle unit 456 relative to the chassis 432. In theillustrated example, the motor/fan assembly 462 is coupled with thehousing 458 defining the suction nozzle 434 by a fixed link 464. Whileonly shown schematically in FIG. 19, the fixed link 464 may be definedby a body, housing or casing of the nozzle unit 456 that houses,carries, or defines components of the nozzle unit 456, such as themotor/fan assembly 462, the suction nozzle 434, and the agitator 460.

The mechanical linkage 436 of the seventh example includes a pivot link466 coupling the nozzle unit 456 with the carriage 450. The pivot link466 is orientated at an obtuse angle with respect to the fixed link 464.An upper joint 468 connects the pivot link 466 to the nozzle unit 456and a lower joint 470 connects the pivot link 466 to the carriage 450.The joints 468, 470 can be revolute joints having one degree of freedom.The upper joint 468 can be collinear with an axis defined by a shaft ofthe motor/fan assembly 462, and the lower joint 470 can be collinearwith the axis of the rear wheels 452 and the pivot connection 446,although in other configurations the joint axis may be offset from oneor both of these the axes. A link stop 472 can be provided for the fixedlink 464 for limiting the forward movement of the nozzle unit 456.

To accommodate for the movement of the motor/fan assembly 462 relativeto the chassis 432, the vacuum cleaner 430 can be provided with aworking air duct 476 between the separating and collection assembly 442and the motor/fan assembly 462 that is flexible, pivotable, or otherwisehas sufficient clearance for movement of the nozzle unit 456 relative tothe chassis 432. A portion of the working air duct 476 may extendthrough the pivot connection 446 between the upright unit 438 and thebase unit 444, or may pass exteriorly of the pivot connection 446.

In the present example, the working air duct 476 includes an uprightduct segment 478 and a base duct segment 480. The upright duct segment478 can be provided partially or entirely in the upright unit 338 andcan extend from an air outlet of the separating and collection assembly442 and the base duct segment 480. The base duct segment 480 can beprovided partially or entirely in the base unit 342 and can extend fromthe upright duct segment 478 to an inlet of the motor/fan assembly 462.In other configurations, the segments 478, 480 may be in fluidcommunication with the outlet of the separating and collection assembly442 and the inlet of the motor/fan assembly 462, rather than physicallyextending to them.

The duct segments 478, 480 can be connected at a duct joint 482. Theduct joint 482 can be a revolute joint having one degree of freedom. Theduct joint 482 can be collinear with the axes of the rear wheels 452,the pivot connection 446, and the lower joint 470, although in otherconfigurations the joint axis may be offset from one or more of thesethe axes. A duct stop 474 can be provided for limiting the forwardrotation of the base duct segment 480 relative to the upright ductsegment 478 and chassis 432.

The pivot connection 446 can define a first pivot axis for the uprightunit 438 relative to the base unit 444 that is collinear with therotational axes of the rear wheels 452, the lower joint 470, and theduct joint 482. In addition, the pivot connection 446 may alsooptionally include a swivel coupling 484 permitting the upright unit 438to be turned left or right relative to the base unit 444.

FIGS. 19-20 show the base unit 444 in various operational positions.FIG. 19 shows the base unit 444 in a neutral operational position; thebase unit 444 may be in the neutral operational position when theresistance on the nozzle unit 456 is below a predetermined amount. Forexample, the resistance on the nozzle unit 456 in FIG. 19, whether thebase unit 444 is moving forward or backward over the surface to becleaned, can be less than or equal to the weight of the nozzle unit 456.In the neutral operational position, the suction nozzle 434 is loweredto the surface to be cleaned, with the fixed link 464 resting on thelink stop 472. Also, in this position, the base duct segment 480 restson the duct stop 474

FIG. 20 shows a raised operational position of the nozzle unit 456during a forward stroke of the base unit 444. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 456 inan opposing direction to the direction of movement of the base unit 444,the mechanical linkage 436 lifts the suction nozzle 434 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 434, while the chassis 432 continues forward, and the fixed link464 transmits the force on the suction nozzle 434 to the pivot link 466,which pivots about the lower joint 470, thereby raising the entirenozzle unit 456, including the suction nozzle 434, the agitator 460, andthe motor/fan assembly 462. The movement of the nozzle unit 456 alsorotates the base duct segment 480 relative to the upright duct segment478. In the raised position, the suction nozzle 434 is both verticallyand horizontally displaced with respect to the neutral operationalposition. The horizontal displacement results in the suction nozzle 434being horizontally closer to the carriage 450.

FIG. 21 is a schematic side view of a vacuum cleaner 490 according to aneighth aspect of the present disclosure. The eighth example issubstantially similar to the second example, and like elements arereferred to with the same reference numerals. The eighth exampleincludes a pivot connection 492 including, but not limited to, auniversal joint, provided between the upright unit 68 and the base unit74 and a working air duct 494 between the separating and collectionassembly 72 and the motor/fan assembly 82 that accommodate for themovement of the motor/fan assembly 82 relative to the chassis 62. Aportion of the working air duct 494 may extend through the pivotconnection 492, or may pass exteriorly of the pivot connection 492.

In the present example, the working air duct 494 includes an uprightduct segment 496 and a base duct segment 498. The upright duct segment496 can be provided partially or entirely in the upright unit 68 and canextend from an air outlet of the separating and collection assembly 72and the base duct segment 498. The base duct segment 498 can be providedpartially or entirely in the base unit 74 and can extend from theupright duct segment 496 to an inlet of the motor/fan assembly 82. Thebase duct segment 498 can be configured to compress and expand along itslongitudinal axis. In one example the base duct segment 498 can includea bellows-type construction. In other configurations, the segments 496,498 may be in fluid communication with the outlet of the separating andcollection assembly 72 and the inlet of the motor/fan assembly 82,rather than physically extending to them.

The duct segments 496, 498 can be connected at a duct joint 500. Theduct joint 500 can be a revolute joint having one degree of freedom. Theduct joint 500 can be collinear with the rotational axis of the rearwheels 108, although in other configurations the joint axis may beoffset from the rotational axis.

FIGS. 21-23 are show the base unit 74 in various operational positions;with respect to the mechanical linkage 66, the operational positionscorrespond to those shown and described for FIGS. 4-6, respectively.During movement from the neutral operational position (FIG. 21) toeither raised position (FIG. 22 or FIG. 23), the movement of the nozzleunit 78 also rotates the base duct segment 498 relative to the uprightduct segment 496. On a forward stroke as shown in FIG. 22, the base ductsegment 498 rotates rearwardly and compresses whereas on a rearwardstroke as shown in FIG. 23, the base duct segment 498 rotates forwardlyand expands relative to the neutral position shown in FIG. 21.

FIG. 24 is a schematic view of a vacuum cleaner 510 according to a ninthaspect of the present disclosure. The vacuum cleaner 510 includes achassis 512, a suction nozzle 514, and a mechanical linkage 516 formoving the suction nozzle 514 relative to the chassis 512. In thepresent example, the vacuum cleaner 510 is schematically illustrated asan upright-type vacuum cleaner, in which in which an upright unit 518having a handle 520 is pivotally mounted to a base unit 522, which movesover the surface to be cleaned. A pivot connection 524, including, butnot limited to, a universal joint, can be provided between the uprightunit 518 and the base unit 522. The chassis 512 may include the uprightunit 518 as well as a portion of the base unit 522. Many of thecomponents of the vacuum cleaner 510 that are not directly germane tothe mechanical linkage 516 are not shown for purposes of simplification,but rather are understood to be incorporated in the examples from thedescription of FIG. 1; such components may include, but are not limitedto, a separating and collection assembly, a suction source, and/or anagitator drive assembly.

The base unit 522 includes a chassis portion 526 coupled to the suctionnozzle 514 by the mechanical linkage 516. The chassis portion 526includes a carriage 528 having a set of rear wheels 530 and a set offront wheels 532 for maneuvering the base unit 522 over a surface to becleaned.

The suction nozzle 514 is defined by a nozzle unit 534, and the entirenozzle unit 534 may be coupled to the carriage 528 via the mechanicallinkage 516. The nozzle unit 534 includes a housing 536 that defines apartially enclosed space for housing, carrying, or defining severalcomponents, including the suction nozzle 514 and an agitator (notshown). The agitator can be a rotatable brushroll, such as, for example,the brushroll 538 shown in FIG. 12; however, it is within the scope ofthe present disclosure for other types of agitators to be used, such asa stationary brush or dual rotating brushrolls.

The mechanical linkage 516 of the ninth example includes a four-barlinkage from which the nozzle unit 534 hangs or is suspended. The fourbodies making up the four-bar linkage include a supporting body 540supporting the nozzle unit 534, the carriage 528, a rear link 542, and afront link 544 connected in a loop by joints, with the links 542, 544joining the carriage 528 and the supporting body 540. In the presentexample, joints 546, 548 connect the carriage 528 to the rear link 542and the front link 544, respectively, and can be collinear with therotational axes of the wheels 530, 532, although in other configurationsthe joints 546, 548 may be offset from the rotational axes. Joints 550,552 connect the supporting body 540 to the rear link 542 and the fontlink 544, respectively. The joints can be revolute joints having onedegree of freedom. While not shown in FIG. 24, a pair of four-barlinkages may be provided, and laterally spaced on either side of thebase unit 522, in a similar manner as described for the second examplein FIG. 2.

The vacuum cleaner 510 of the ninth example further includes a reliefvalve 554 in the airflow pathway between the suction nozzle 514 and thesuction source (not shown) for selectively reducing the suction force atthe suction nozzle 514 by allowing the passage of ambient air intoairflow pathway downstream of the suction nozzle 514, rather thanentirely through the suction nozzle 514 alone. The relief valve 554 isconfigured for cooperative operation with the mechanical linkage 516,such that the relief valve 554 opens when a predetermined amount ofresistance is applied to the nozzle unit 534 in order to draw ambientair into airflow pathway downstream of the suction nozzle 514, whichreduces the suction force at the suction nozzle 514. When the resistanceon the nozzle unit 534 is below the predetermined amount, the reliefvalve 554 is closed in order to draw the full suction force at thesuction nozzle 514.

For the example of the relief valve 554 illustrated herein, the reliefvalve 554 is provided on the nozzle unit 534 and includes a bleed hole558 is provided in the nozzle housing 536 and a valve body 560 moveablerelative to the bleed hole 558. The valve body 560 is fixedly coupledwith chassis 512, such that the bleed hole 558 moves relative to thevalve body 560 as the nozzle unit 534 moves relative to the chassis 512.For example, a valve link 562 can fixedly couple the valve body 560 tothe chassis 512. In the present example, the link 562 extends betweenthe valve body 560 and the joint 548 connecting the carriage 528 and thefront link 544, although in other configurations the valve link 562 maybe coupled to other portions of the chassis 512.

The valve body 560 is further provided with a first valve opening 564and a second valve opening 566 disposed forwardly of the first valveopening 564. The valve openings 564, 566 extend through the valve body560, and can be selectively aligned with the bleed hole 558 to fluidlycommunicate the interior of the nozzle housing 536 with the atmospherein order to draw ambient air in through the bleed hole 558. The openings564, 566 are spaced from each other, and the space between the openings564, 566 on the valve body 560 can be selectively aligned with the bleedhole 558 in order to close the bleed hole 558.

FIGS. 24-26 show the base unit 522 in various operational positions.FIG. 24 shows the base unit 522 in a neutral operational position; thebase unit 522 may be in the neutral operational position when theresistance on the nozzle unit 534 is below a predetermined amount. Forexample, the resistance on the nozzle unit 534 in FIG. 12, whether thebase unit 522 is moving forward or backward over the surface to becleaned, can be less than or equal to the weight of the nozzle unit 534.In the neutral operational position, the suction nozzle 514 is loweredto the surface to be cleaned. Further, the relief valve 554 is closed inthe neutral operational position, with the valve body 560 closing thebleed hole 558.

FIG. 25 shows a first raised operational position of the nozzle unit 534during a forward stroke of the base unit 522. On a forward stroke, if apredetermined amount of resistance is applied to the nozzle unit 534 inan opposing direction to the direction of movement of the base unit 522,the mechanical linkage 516 lifts the suction nozzle 514 away from thesurface. Specifically, the resistance arrests movement of the suctionnozzle 514, while the chassis 512 continues forward, and the carriage528 acts as a ground link or frame about which the front link 544 ispivoted. The movement of the front link 544 is transmitted to the rearlink 542 via the supporting body 540, which acts as a floating link orcoupler between the grounded front and rear links 542, 544. As the links542, 544 pivot rearwardly, the supporting body 540 floats upwardly andrearwardly and the entire nozzle unit 534 is raised and pulledrearwardly, closer to the chassis 512. In the raised position, thesuction nozzle 514 is both vertically and horizontally displaced withrespect to the neutral operational position. The horizontal displacementresults in the suction nozzle 514 being horizontally closer to thecarriage 528. Further, as the nozzle unit 534 is raised and pulledrearwardly, closer to the chassis 512, the bleed hole 558 is broughtinto alignment with the first valve opening 564 in the valve body 560.

The suction source thereby draws ambient air in through the bleed hole558 as well as through the suction nozzle 514, which further reduces thesuction force drawn at the suction nozzle 514.

FIG. 26 shows a second raised operational position of the nozzle unit534 during a rearward stroke of the base unit 522. On a rearward stroke,if a predetermined amount of resistance is applied to the nozzle unit534 in an opposing direction to the direction of movement of the baseunit 522, such as from an obstacle 158 as shown or from nozzle lock-downregardless of whether an obstacle 158 is present, the mechanical linkage516 lifts the suction nozzle 514 away from the surface. Specifically,the resistance arrests movement of the suction nozzle 514, while thechassis 512 continues rearward, and the links 542, 544 pivot forwardlyto move the supporting body 540 upwardly and forwardly, thereby raisingthe entire nozzle unit 534. In the raised position, the suction nozzle514 is both vertically and horizontally displaced with respect to theneutral operational position. The horizontal displacement results in thesuction nozzle 514 being horizontally further from the carriage 528.Further, as the nozzle unit 534 is moved further from the chassis 512,the bleed hole 558 is brought into alignment with the second valveopening 566 in the valve body 560. The suction source thereby drawsambient air in through the bleed hole 558 as well as through the suctionnozzle 514, which further reduces the suction force drawn at the suctionnozzle 514.

It is noted that the relief valve 554 may be provided on any of theexamples described herein. For example, any of the examples discussedwith respect to FIGS. 1-23 can includes a relief valve 554 in theairflow pathway between the suction nozzle and the suction sourceselectively reducing the suction force at the suction nozzle 514. Therelief valve 554 is configured for cooperative operation with themechanical linkage 34, 66, 166, 286, 336, 386, 436, such that the reliefvalve 554 opens when a predetermined amount of resistance is applied tothe nozzle unit 40, 78, 178, 304, 354, 402, 456, and closes when theresistance on the nozzle unit 40, 78, 178, 304, 354, 402, 456 is belowthe predetermined amount. For the example of the relief valve 554illustrated herein, the relief valve 554 can include the bleed hole 558on the nozzle unit 40, 78, 178, 304, 354, 402, 456, and the valve body560 fixedly coupled with the chassis 36, 62, 162, 282, 332, 382, 432.

Also, while the relief valve 554 discussed herein is shown as beingprovided on a vacuum cleaner in which the suction nozzle is displacedhorizontally and vertically, relative to the surface to be cleaned, therelief valve 554 can operate with a suction nozzle that is not displacedvertically. For example, in another example, the relief valve can beprovided on a vacuum cleaner in which the nozzle unit moves onlyhorizontally relative to the chassis, via a mechanical linkage. FIG. 27shows one such example, and is a schematic view of a vacuum cleaneraccording to a tenth aspect of the present disclosure. The vacuumcleaner 510 is substantially similar to the vacuum cleaner 510 describedfor FIG. 24, and like elements are identified with the same referencenumerals. In the tenth example, the vacuum cleaner 510 includes amechanical linkage 570 including a compression spring 572 between thenozzle unit 534 and chassis 526. The nozzle unit 534 moves horizontallyrelative to the chassis 526 when a predetermined amount of resistancegreater than the spring force of the compression spring 572 is appliedto the nozzle unit 534, whether the base unit 522 is moving forward orbackward over the surface to be cleaned. The relief valve 554 operatesas described above for FIGS. 24-26.

The vacuum cleaner disclosed herein includes an improved suction nozzle.One advantage that may be realized in the practice of some examples ofthe described vacuum cleaner is that the suction nozzle can beautomatically adjusted based on resistance, and has both horizontal andvertical freedom relative to the chassis of the vacuum cleaner, whichcan reduce push force on all cleaning surfaces compared to prior artdesigns. Vacuuming a super soft carpet can prove challenging withconventional vacuum cleaners since the densely-packed fibers and carpetbacking can impede airflow and increase the push force required to movethe vacuum cleaner over the carpet. Indeed, the suction nozzle of aconventional vacuum cleaner can become virtually sealed or “locked” ontothe carpet, preventing a user from pushing the vacuum cleaner across thefloor surface. To alleviate the “lock-down” issue on a conventionalvacuum cleaner, a user can increase the nozzle height setting, but thisforms a large gap between the suction nozzle and the carpet, whichincreases air leaks and hinders cleaning performance. The vacuum cleanerof the present disclosure automatically raises the suction nozzle uponencountering a predetermined amount of resistance, and alsoautomatically lowers the suction nozzle when the resistance is removedor overcome. In addition to having the freedom to move vertically, thesuction nozzle is also provided with the freedom to move horizontally,since the suction nozzle is not horizontally connected in a fixed mannerto the chassis of the vacuum cleaner. The mechanical linkage convertshorizontal resistance forces to vertical movement of the suction nozzle,which spaces the suction nozzle from the surface to be cleaned. Inaddition to the “lock-down” issue, this automatic adjustment can also beuseful when encountering other sources of resistance, such as athreshold or transitioning from a bare floor to carpet.

Another advantage that may be realized in the practice of some of thedescribed vacuum cleaner is that a suction relief valve can beautomatically opened or closed based on resistance, thereby furtherreducing the suction force drawn at the suction nozzle.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that thisis by way of illustration and not of limitation. Reasonable variationand modification are possible with the scope of the foregoing disclosureand drawings without departing from the spirit of the invention which,is defined in the appended claims. Hence, specific dimensions and otherphysical characteristics relating to the embodiments disclosed hereinare not to be considered as limiting, unless the claims expressly stateotherwise.

What is claimed is:
 1. A vacuum cleaner, comprising: a housing includingan upright unit having a handle operably coupled to a base unit, thebase unit including a chassis having a carriage fixed to the chassis andwheels coupled to the carriage; a nozzle unit with a suction nozzle; asuction source in fluid communication with the suction nozzle andadapted for generating a working airstream along a working air path; amechanical linkage coupling the nozzle unit to the carriage of thechassis, wherein the mechanical linkage comprises at least two degreesof freedom to displace the nozzle unit relative to the surface to becleaned, independently of the chassis, such that the suction nozzle canraise and float relative to the chassis wherein the mechanical linkageis configured to automatically lift the suction nozzle away from thesurface to be cleaned upon a predetermined force being applied to thenozzle unit during movement of the base unit across the surface to becleaned; and a working air duct forming at least a portion of theworking air path from the suction nozzle to the suction source, theworking air duct adapted for accommodating the float of the suctionnozzle.
 2. The vacuum cleaner of claim 1, further comprising aseparating and collection assembly for separating and collecting liquidand/or debris from the working airstream for later disposal, theseparating and collection assembly located on the upright unit.
 3. Thevacuum cleaner of claim 2 wherein the working air duct comprises a firstworking air duct between the nozzle unit and the separating andcollection assembly and a second working air duct between the separatingand collection assembly and the suction source.
 4. The vacuum cleaner ofclaim 3 wherein the first working air duct and the second working airduct are at least one of flexible, pivotable, or have clearance foraccommodating movement of the nozzle unit relative to the chassis. 5.The vacuum cleaner of claim 4 wherein the first working air duct and thesecond working air duct are both flexible hose segments.
 6. The vacuumcleaner of claim 1 wherein the working air duct is at least one offlexible, pivotable, or has clearance to accommodate movement of thenozzle unit relative to the chassis.
 7. The vacuum cleaner of claim 1wherein at least a portion of the working air duct is adapted tocompress and expand along a longitudinal axis of the portion of theworking air duct.
 8. The vacuum cleaner of claim 1 wherein the workingair duct comprises a bellows-type construction.
 9. The vacuum cleaner ofclaim 1 wherein a first portion of the working air duct and a secondportion of the working air duct are coupled via a duct joint having onedegree of freedom.
 10. The vacuum cleaner of claim 1 wherein movementfrom a neutral operational position to a raised position of the nozzleunit rotates at least a portion of the working air duct.
 11. The vacuumcleaner of claim 10 wherein the working air duct comprises an uprightduct segment provided partially or entirely with the upright unit and abase duct segment provided partially or entirely with the base unit. 12.The vacuum cleaner of claim 10 wherein the at least a portion of theworking air duct rotates rearwardly and compresses.
 13. The vacuumcleaner of claim 1 wherein the nozzle unit further comprises an agitatorprovided adjacent to the suction nozzle for agitating debris on thesurface to be cleaned.
 14. The vacuum cleaner of claim 13 wherein theagitator comprises a rotatable brushroll, and the nozzle unit furthercomprises a motor operably coupled with the rotatable brushroll.
 15. Thevacuum cleaner of claim 1, further comprising a pivot connection locatedbetween the upright unit and the base unit.
 16. The vacuum cleaner ofclaim 15 wherein a portion of the working air duct extends through thepivot connection.
 17. The vacuum cleaner of claim 1 wherein thepredetermined force is greater than a weight of the nozzle unit.
 18. Thevacuum cleaner of claim 1 wherein the nozzle unit is moveable betweentwo different raised operational positions, comprising: a first raisedoperational position, wherein the mechanical linkage is configured toautomatically displace the suction nozzle toward the chassis to thefirst raised operational position upon a predetermined resistance forcebeing applied to a forward side of the nozzle unit during a forwardstroke of the vacuum cleaner across the surface to be cleaned; and asecond raised operational position, wherein the mechanical linkage isconfigured to automatically displace the suction nozzle away from thechassis to the second raised operational position upon a predeterminedresistance force being applied to a rearward side of the nozzle unitduring a rearward stroke of the vacuum cleaner across the surface to becleaned.
 19. The vacuum cleaner of claim 1 wherein the mechanicallinkage comprises a cam joint that controls the position of the nozzleunit relative to the chassis and a pin-in-slot joint having two degreesof freedom and that limits the movement of the nozzle unit relative tothe chassis.
 20. The vacuum cleaner of claim 1 wherein the mechanicallinkage comprises a rear link and a front link coupling the carriagewith the nozzle unit in a loop with multiple joints.